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首页> 外文期刊>Bulletin of earthquake engineering >Earthquake-reactivated landslide scenarios in Southern Italy based on spectral-matching input analysis
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Earthquake-reactivated landslide scenarios in Southern Italy based on spectral-matching input analysis

机译：基于频谱匹配输入分析的意大利南部地震复活的滑坡情景

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The Tyrrhenian portion of the Calabria region (southern Italy) is particularly prone to landslides as a consequence of intense morphodynamic processes. These processes affect the slopes that are composed of highly jointed metamorphic rock masses. Moreover, the frequent intense rainfalls and the up toMw7.0 regional earthquakes represent themain landslide triggering factors. An area of approximately 45 km~2 was selected as a test site in the context of a regional project aimed at reconstructing possible earthquake-reactivated landslide scenarios (i.e., referred to already existing landslide masses). An inventory map led to the identification of 175 landslides, including rock slides, earth slides and rock falls. Groundmotion scenarios based on a spectral-matching method were derived to evaluate the expected earthquake-induced displacements of the existing landslides.Naturally recorded acceleration time histories were selected from international ground-motion databases based on a similarity index and considered representative of the seismological features of the considered seismic sources (i.e., epicentral distance, magnitude, focal mechanism). Spectral attenuation was considered, according to well-established attenuation laws, to define the expected response spectrum at the outcropping bedrock corresponding to each existing landslide. Subsequently, the selected natural records weremodified to guarantee spectralmatching with the attenuated response spectra at each landslide site. The derived time histories were used to compute coseismic displacements via the classic Newmark's sliding-block method. Different scenarios of co-seismic landslide displacements or collapse were generated for different pore-water pressure hypotheses. The strongest Mw > 6 seismic scenario (Messina Straits seismogenic source) indicated an exceedance probability of earthquake-induced co-seismic landslide collapse varying from 20 to 55% with the increasing severity of the pore-water pressures. This probability corresponds to a percentage of co-seismic landslide displacements up to 40% of the total inventoried landslides. The exceedance probability indicated that co-seismic landslide collapse drops below 20% for Mw < 6 seismic scenarios. In contrast, if a uniform probability is assumed for the seismic action occurrence, i.e., return periods of 475 and 2,475 years, the total percentage of landslide co-seismic displacements could be as high as 70 and 90%, respectively, for the considered pore-water pressures.
机译：由于强烈的形态动力学过程，卡拉布里亚地区（意大利南部）的第勒尼安地区特别容易发生滑坡。这些过程会影响由高度节理的变质岩体组成的斜坡。此外，频繁的强降雨和高达Mw7.0的区域地震是引发滑坡的主要因素。在旨在重建可能的地震激活的滑坡情景（即已提及的滑坡体）的区域项目的背景下，选择了约45 km〜2的区域作为测试地点。清单图确定了175个滑坡，包括岩滑，土滑和岩崩。推导了基于谱匹配法的地震动情景，以评估地震对现有滑坡的预期位移。基于相似性指标，从国际地震动数据库中选择了自然记录的加速时间历史记录，并认为这代表了地震的特征。考虑的地震源（即震中距离，震级，震源机制）。根据公认的衰减定律，考虑使用频谱衰减来定义对应于每个现有滑坡的露头基岩处的预期响应频谱。随后，对选定的自然记录进行修改，以确保与每个滑坡站点的衰减响应谱匹配。通过经典的纽马克（Newmark）滑块方法，使用导出的时间历史记录来计算同震位移。对于不同的孔隙水压力假设，产生了同震滑坡位移或坍塌的不同情景。 Mw> 6最强的地震情境（墨西拿海峡的震源）表明，随着孔隙水压力的增加，地震诱发的同震滑坡倒塌的可能性从20％到55％不等。此概率对应于同震滑坡位移的百分比，最高可达总清单滑坡的40％。超出概率表明，对于Mw <6地震情景，同震滑坡塌陷降至20％以下。相反，如果假定地震作用发生的概率相同，即475年和2475年的回归期，则对于所考虑的孔隙，滑坡同震位移的总百分比可能分别高达70％和90％ -水压。

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